1. Field of the Invention
This invention relates to poly(oxyalkylene)pyridyl and piperidyl esters and to fuel compositions containing poly(oxyalkylene)pyridyl and piperidyl esters. More particularly, this invention relates to poly(oxyalkylene)pyridyl and piperidyl esters and to the use of such compounds in fuel compositions to prevent and control engine deposits.
2. Description of the Related Art
It is well known that automobile engines tend to form deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports and intake valves, due to the oxidation and polymerization of hydrocarbon fuel. These deposits, even when present in relatively minor amounts, often cause noticeable driveability problems, such as stalling and poor acceleration. Moreover, engine deposits can significantly increase an automobile's fuel consumption and production of exhaust pollutants. Therefore, the development of effective fuel detergents or "deposit control" additives to prevent or control such deposits is of considerable importance and numerous such materials are known in the art.
For example, amino phenols are known to function as detergents/dispersants, antioxidants and anti-corrosion agents when used in fuel compositions. U.S. Pat. No. 4,320,021, issued Mar. 16, 1982 to R. M. Lange, for example, discloses amino phenols having at least one substantially saturated hydrocarbon-based substituent of at least 30 carbon atoms. The amino phenols of this patent are taught to impart useful and desirable properties to oil-based lubricants and normally liquid fuels. Similar amino phenols are disclosed in related U.S. Pat. No. 4,320,020, issued Mar. 16, 1982 to R. M. Lange.
Similarly, U.S. Pat. No. 3,149,933, issued Sep. 22, 1964 to K. Ley et al., discloses hydrocarbon-substituted amino phenols as stabilizers for liquid fuels.
U.S. Pat. No. 4,386,939, issued Jun. 7, 1983 to R. M. Lange, discloses nitrogen-containing compositions prepared by reacting an amino phenol with at least one 3- or 4-membered ring heterocyclic compound in which the hetero atom is a single oxygen, sulfur or nitrogen atom, such as ethylene oxide. The nitrogen-containing compositions of this patent are taught to be useful as additives for lubricants and fuels.
More recently, certain poly(oxyalkylene) esters have been shown to reduce engine deposits when used in fuel compositions. U.S. Pat. No. 5,211,721, issued May 18, 1993 to R. L. Sung et al., for example, discloses an oil soluble polyether additive comprising the reaction product of a polyether polyol with an acid represented by the Formula RCOOH in which R is a hydrocarbyl radical having 6 to 27 carbon atoms. The poly(oxyalkylene) ester compounds of this patent are taught to be useful for inhibiting carbonaceous deposit formation, motor fuel hazing, and as ORI inhibitors when employed as soluble additives in motor fuel compositions.
Poly(oxyalkylene) esters of amino- and nitrobenzoic acids are also known in the art. For example, U.S. Pat. No. 2,714,607, issued Aug. 2, 1955 to M. Matter, discloses polyethoxy esters of aminobenzoic acids, nitrobenzoic acids and other isocyclic acids. These polyethoxy esters are taught to have excellent pharmacological properties and to be useful as anesthetics, spasmolytics, analeptics and bacteriostatics. U.S. Pat. Nos. 2,714,608; 2,714,609; and 2,714,610, all issued to M. Matter, disclose similar polyethoxy esters.
Similarly, U.S. Pat. No. 5,090,914, issued Feb. 25, 1992 to D. T. Reardan et al., discloses poly(oxyalkylene) aromatic compounds having an amino or hydrazinocarbonyl substituent on the aromatic moiety and an ester, amide, carbamate, urea or ether linking group between the aromatic moiety and the poly(oxyalkylene) moiety. These compounds are taught to be useful for modifying macromolecular species such as proteins and enzymes. U.S. Pat. Nos. 5,081,295; 5,103,039; and 5,157,099; all issued to D. T. Reardan et al., disclose similar poly(oxyalkylene) aromatic compounds.
U.S. Pat. No. 4,328,322, issued Sep. 22, 1980 to R. C. Baron, discloses amino- and nitrobenzoate esters of oligomeric polyols, such as poly(ethylene) glycol. These materials are used in the production of synthetic polymers by reaction with a polyisocyanate. Similar materials are disclosed in U.S. Pat. No. 4,515,981, issued May 7, 1985 to K. Otani et al., and in U.S. Pat. Nos. 5,039,775 and 5,086,153, both issued to Y. Oyaizu.
U.S. Pat. No. 5,407,452, issued Apr. 18, 1995 to R. E. Cherpeck, discloses poly(oxyalkylene) aromatic esters containing a nitro, amino, N-alkylamino, or N,N-dialkylamino moiety on the aromatic ring. These compounds are taught to be useful as fuel additives for the prevention and control of engine deposits.
Commonly-assigned copending U.S. patent application Ser. No. 09/141,997, filed Aug. 28, 1998, discloses pyridyl and piperidyl esters of polyalkylphenoxyalkanols which are described as being useful as fuel additives for the control of engine deposits.
Commonly-assigned copending U.S. patent application Ser. No. 09/141,633, filed Aug. 28, 1998, discloses ethers of polyalkyl or polyalkenyl N-hydroxyalkyl succinimides, wherein the ether moiety may be substituted phenyl, pyridyl or piperidyl. These compounds are taught to be useful as fuel additives for the control of engine deposits.